You're right, it is the CO2 emissions, but they're effectively unavoidable. We do not have enough renewable energy sources built right now to support even the

You're right, it is the CO2 emissions, but they're effectively unavoidable. We do not have enough renewable energy sources built right now to support even the current load. Additional load means dirty power plants stay online longer as we wait for enough green energy sources to come online. Even if all the miners were running on entirely green energy, there's an opportunity cost. That green energy could be used to power homes and we could shut down coal power plants. I don't care that you bought 9,000 solar panels to power your mining farm, because that's 9,000 solar panels that could have been hooked up to the grid. I don't want to rain on anyone's parade. I find cryptocurrencies interesting and would like for them to exist, but we're in a terrible position to be pissing away electricity right now. In the scheme of ways to use electricity, Bitcoin is a pretty frivolous use too. The electricity consumption is just so outsized compared to the actual physical gain (and I'm not talking about money made from speculating). If I were the ruler of the world, I'd give it a transaction tax that was proportional to the percentage of load generation that isn't renewable. If 40% of our energy is still dirty, then there's a 40% transaction tax. If we can get that down to 5%, then there's only a 5% tax. I don't see a reason to ban them, we just need to cut power consumption and thus CO2 emissions wherever we can.